JPH0325723A - Magnetic recording medium and production thereof - Google Patents

Abstract

PURPOSE:To strengthen the adhesive strength of a lubricating layer and to provide the longer life and higher reliability of the magnetic recording medium by uniformly dispersing and sticking an intervening material for strengthening the adhesive strength consisting of one kind of metal atoms and compd. thereof to the surface of a protective layer without covering the entire surface. CONSTITUTION:An underlying layer 2 consisting of Cr, a magnetic layer 3 consisting of a CO-Ni alloy, and the protective layer 4 consisting of sputtered carbon are formed by sputtering in this order on an Al disk substrate 1 on which an Ni-P plating film is previously formed. The sputtering of the layer 4 is executed by a direct sputtering method using a target consisting of graphite and 5mTorr gaseous Ar pressure. The Ni atoms 6 are stuck by the sputtering on this substrate and after the substrate is immersed in a Freon soln. contg. a fluorine lubricant 5, the substrate is pulled up at a specific speed to form the lubricant layer. The durability of the produced disk is tested by a CSS testing machine. The desirable result is obtd. at 3 to 60% surface atom occupying rate of the metal elements.

Description

[Detailed description of the invention]

[Industrial Application Field 1] The present invention relates to a magnetic recording medium that is widely used as a storage medium for electronic devices such as electronic computers, word processors, and other information equipment, and audio tapes and video tapes, as well as a method for manufacturing the same and a method for using the same. Regarding applied products. [Prior Art] In the field of magnetic recording, the amount of information required continues to increase year by year, and it is desired to increase the capacity to 1M and increase the speed. For this reason, the direction of recording density L is the biggest issue, and it is essential to improve the structure and materials of recording media. In terms of structure, the most effective method is to make the recording layer thinner. Traditionally, magnetic powder was mixed with a resin called a binder and coated to form the magnetic layer, but recently thin films of the magnetic material itself have been vacuum-deposited. Thin-film magnetic disks and vapor-deposited magnetic tapes formed by methods such as lithography and sputtering have been developed. However, as the recording layer becomes thinner, the mechanical strength of the recording layer becomes weaker, so it is necessary to protect it. Therefore, for this reason, it has traditionally been necessary to cover the surface of the recording layer with a protective film that is less susceptible to abrasion and breakage damage, and to apply lubricant thereon to minimize damage when sliding with the magnetic head. has been carried out. Therefore, the overall quality of the protective film and lubricant determines the lifespan and reliability of the magnetic recording medium. Poor-quality carbon-based thin films and carbides have traditionally been used as protective films for thin-film magnetic recording media, due to the excellent wear resistance of these materials. However, it has been found that the adsorption power of lubricants to these protective films is generally weak. For example, evidence of this is that cleaning with a Fluorox-based carbon solvent removes most of it. Various proposals have been made for the purpose of firmly bonding lubricants to protective films. For example, JP-A No. 62-234226 has an example of a lubricant with a functional group attached to the end of the molecule that is easily adsorbed, and JP-A No. 61-210519 has an example of a lubricant with a functional group attached to the end of the molecule, and JP-A No. 61-210519 has an example of a lubricant with a functional group attached to the end of the molecule. Methods such as coupling are disclosed. Furthermore, JP-A No. 61-220120 discloses a method in which a metal oxide film is formed on a carbon protective layer and a lubricant with a polar group is applied thereto.

[asn that the invention aims to solve]However, in the conventional method of covalently bonding the lubricant and the protective film to strengthen the adhesion as described above, if there are unreacted substances, they may impair lubricity or change over time. It causes In addition, the reactivity of the bonded part is higher than other parts, and there are problems such as being easily decomposed by the heat during sliding.Also, if the bond breaks due to decomposition during sliding, there is a small possibility that it will bond again. ,
It is difficult to replenish lubricant. Moreover, it is extremely difficult to form such bonds uniformly and with sufficient density over the entire surface of the protective film. On the other hand, when a metal oxide film is provided on the protective film and a lubricant with a polar group is adsorbed to this film to strengthen the bonding force, this metal oxide film is formed through a thin lubricant layer. Since it rubs directly against the sliding part of the magnetic head, the metal oxide wear particles (debris) generated by this sliding damage the underlying protective film, and even if a strong protective film is installed, the protective film will not work. characteristics are not fully utilized. As described above, since metal oxide films are weaker than carbon films, carbides, etc. that are generally used as protective film materials, there is a problem in that they weaken the durability of the magnetic recording medium as a whole. Therefore, an object of the present invention is to solve the above-mentioned conventional problems, and the first object is to provide an improved magnetic recording medium in which the bonding force between the protective film and the lubricant is further strengthened. The purpose is to provide its manufacturing method, and the third purpose is to provide its applied products. [Means for Solving the Problems] The present inventors have investigated in detail the relationship between the lubricant application method, applied state, application amount, etc., and the frictional wear characteristics of a magnetic recording medium, and have found that the covalent bond Instead, the most effective way to extend the life of a magnetic recording medium is to use chemical adsorption to uniformly and firmly adsorb the lubricant to the protective film, and to prevent the characteristics of the protective film from changing. I found out. If the adsorption force between the lubricant and the protective film surface itself is large, lubrication is less likely to run out, and even if it does occur, it can be repaired by adsorption again. It has been found that in order to increase the bonding strength with the lubricant, it is possible to have an element other than carbon, especially a metal atom, or a compound thereof on the surface of the protective film, and to allow the lubricant to be adsorbed through this. Furthermore, in order to achieve this without impairing the properties of the protective film, we have found that it is better to mix the protective film material and the gold RIM element or its compound on the surface of the protective film. The present invention has been made based on the above-mentioned findings, and the first object is to sequentially laminate at least a magnetic recording layer made of a ferromagnetic material, a protective layer, and a lubricating layer on a non-magnetic substrate. In the magnetic recording medium, an adhesion-strengthening intervening substance made of at least one metal atom and a compound thereof is uniformly dispersed on the surface of at least the protective layer while exposing a part of the protective layer without covering the entire surface of the protective layer. This is accomplished by a magnetic recording medium having a lubricating layer attached thereto to enhance the adhesion of the lubricating layer to the protective layer. Further, it is preferable that the surface atomic occupancy of the adhesion-strengthening intervening substance to be adhered to the surface of the protective layer is 0.5 to 80%. Note that the surface atomic occupancy refers to the occupancy of the adhesion-strengthening intervening substance in the entire area of the surface of the protective layer. Further, the metal atoms constituting the adhesion-strengthening intervening substance include metal atoms and/or compounds thereof, which have lower ionization energy than hydrogen, and the compounds are selected from the group of hydroxides, salts, and oxides. It is preferable that the material consists of at least one kind. The adhesion-strengthening intervening substance may be scattered on the surface of the protective layer, or it may be dispersed or mixed within the protective layer and a portion thereof may be exposed on the surface of the protective layer, thereby substantially forming the surface of the protective layer. They may be scattered. What is important in the present invention is that the entire surface of the protective layer is not completely covered with this adhesion-strengthening intervening substance, that is, that the surface atomic occupancy of this substance is not 100%. When this adhesion-strengthening intervening substance is dispersed or mixed in the protective layer, it is preferable to create a concentration gradient so that it is distributed more on the surface than inside the layer. The protective layer is selected from at least one of carbon, carbide, nitride, and oxide having high hardness,
Particularly preferred is a carbon-based protective film. The lubricant is preferably a chain organic compound having at least one end group containing an unpaired electron, an electron-donating atom, or an atom having a functional group, and containing fluorine in the main chain. The second object of the present invention is to provide a magnetic recording medium comprising the steps of forming a magnetic recording layer on a non-magnetic substrate, forming a protective layer thereon, and further applying a lubricant thereon. In the manufacturing process of the medium, between the step of forming the protective layer and the step of applying the lubricant, an adhesion-strengthening intervening substance consisting of at least one of metal atoms and metal compounds is applied to the entire surface of the protective layer. This is achieved by a method of manufacturing a magnetic recording medium, which includes a step of uniformly dispersing and adhering the medium while exposing a part thereof so as not to cover it. Preferably, the adhesion-strengthening intervening substance is dispersed and adhered to the surface of the protective layer during the step of forming the protective layer, and in this case, the step of forming the magnetic recording layer on the nonmagnetic substrate; In the manufacturing process of a magnetic recording medium, which includes a step of forming a protective layer thereon and a step of applying a lubricant thereon, the step of forming the protective layer includes forming the protective layer with a carbon-based material. At the same time, when forming this protective layer, an adhesion-strengthening intervening material consisting of at least one of a metal atom and a metal compound is intentionally mixed into the protective layer, and a part thereof is exposed on the surface of the protective layer, thereby strengthening the adhesion. This is achieved by a method for manufacturing a magnetic recording medium comprising the step of forming an intervening substance substantially scattered over the surface of the protective layer. The step of forming the protective layer containing the adhesion-strengthening intervening material is performed by sputtering using a carbon-based target containing the adhesion-strengthening intervening material, or by sputtering a target consisting of the adhesion-strengthening intervening material and carbon. The process involves separately preparing a system target and sputtering them simultaneously or alternately, or using an organic compound vapor containing a metal element or a compound containing a metal element as one of the adhesion-strengthening intervening substances in the raw material gas. This can be achieved by using a chemical vapor phase method to decompose a mixed vapor of organic compound and organic compound in plasma. Furthermore, in the step of forming a protective layer containing this adhesion-strengthening intervening material, plasma is generated using a mixed gas of an organic compound as a carbon raw material and an inert gas, and plasma CVD is performed. It may also be a process of sputtering reinforcing intervening substances. In addition, when adhesion-enhancing intervening substances are mixed in the protective layer as described above, the amount of this substance should be controlled so that it has a concentration gradient so that it is distributed more on the surface than inside the protective layer. is desirable. The metal atoms that control the adhesion-strengthening intervening substances are:
A metal element having an ionization energy lower than that of hydrogen, and a compound thereof preferably at least one selected from the group of hydroxides, salts, and oxides. The adhesion-strengthening intervening substance to be attached to the surface of the protective layer is desirably formed so that its surface atomic occupancy is 0.5 to 80%. This can be easily achieved by setting the conditions for depositing and adhering substances to predetermined values (including plasma CVD) or the like. In addition, in the step of applying the lubricant, the lubricant has a terminal group containing an unpaired electron or an electron-donating atom or a functional group at at least one end, and contains fluorine in the main chain. It is desirable to use chain organic compounds. Hereinafter, the details of the present invention will be explained in more detail using the drawings. FIG. 1 is a conceptual diagram of a cross section of a magnetic recording medium embodying the present invention, in which a base layer 2, a magnetic layer 3, a protective layer 4, and a lubricant layer 5 are formed in this order on a nonmagnetic substrate 1. . The nonmagnetic substrate 1 is, for example, an AQ substrate, a glass substrate, ceramics, etc. in the case of a magnetic disk, and a polymer film such as polyester, polyimide, etc. in the case of a floppy disk, magnetic tape, etc. Although not shown in the drawing, the surface layer of the non-magnetic substrate 1 includes a Ni-P plating film, oxide,
A non-magnetic film such as nitride may be provided to increase the hardness.5 The underlayer 2 is a material for improving the orientation of the magnetic layer, and for example, a Cr sputtered film is used, but it is not limited to this. Of course, there is no need for it. The magnetic layer 3 is a thin film exhibiting ferromagnetism, and is made of Co, such as Co-Ni or Co-Cr.
base alloy, and these and Pt, Ta, W+ Zr, Cr,
Mow Ti + alloy with at least one element selected from V, Si, Ga, etc., Fe, iron nitride, γFe20,,
Cobalt oxide, barium ferrite, etc. can be used. The protective layer 4 protects the magnetic layer from frictional wear, and is made of a carbon film formed by sputtering, a hard carbon film formed by plasma CVD or ion beam deposition, a plasma polymerized film, carbide, nitride, oxide, etc. A material with excellent wear resistance is used. When forming a carbon film by sputtering, a graphite target is used as a cathode to generate plasma of an inert gas such as Ar, or the target is hit with a high-energy ion beam to form a position facing the target. Deposit a carbon film on a substrate located at In addition, when forming a hard carbon film using the plasma CVD method, a plasma is generated using a hydrocarbon gas such as methane, ethane, propane, or an oxygen-containing hydrocarbon gas such as methanol or acetone, and the potential of the plasma is adjusted. Comparatively, the potential of the board is -100V to -2000
CVD is performed at a negative potential of about V. Furthermore, for carbides and nitrides, it is possible to perform sputtering by preparing targets made of these compound materials, but it is also possible to perform sputtering by preparing targets made of single elements constituting each substance separately and sputtering them at the same time. Alternatively, a reactive sputtering method in which sputtering is performed in a nitrogen gas atmosphere may be used. others. Protective layer 4
It is also possible to have a two-layer structure and provide a film with good corrosion resistance such as Si02 on one side. The lubricating layer 5 is, for example, a polymer or oligomer with a molecular weight of about 1,000 to 20,000 having a perfluoro polyether in its main chain, and O, N, P,
Compounds containing an atom with an unpaired electron such as S, an electron-donating atom, or a functional group are preferred. On the surface of the protective film 4, an adhesion-strengthening intervening substance 6 made of metal atoms or their compounds, which is a feature of the present invention, is dispersed and adhered, and the lubricant is adsorbed through this substance 6.
The metal atom may be a single element, or it may be in the form of a compound, such as an oxide, hydroxide, or salt, but hydroxide is preferred because it has a greater effect. This is presumed to be due to the effect of hydrogen bonding between the hydroxyl group and the lubricant terminal group. Another feature of the present invention is that the above-mentioned metal elements do not completely cover the surface of the protective film, but are mixed with atoms constituting the protective film on the surface. Figure 2 is a model showing how metal atoms or their compounds are dispersed on the surface of the protective film 4. As shown in 7 in Figure 2 (.), they are dispersed in an atomic state. is the most preferable. However, in Figure 2 (b
) As shown in item 8, even if it is partially aggregated into an island shape, it is effective as long as it does not completely cover the protective film material. If the surface of the protective film is completely covered with metal or its compound and becomes a film, the strength of the film is insufficient when it slides with a magnetic head, etc., and it is destroyed, resulting in poor sliding durability. I'll let you. On the other hand, when metal atoms or their compounds are selectively dispersed without covering the entire surface of the protective film as in the present invention, the sliding properties are guaranteed to be close to those of the protective film itself, and the lubrication A dramatic effect is produced because only the adsorption power of the agent can be improved. Existing surface analysis techniques such as photoelectron spectroscopy and Auger spectroscopy can be used to examine the amount and distribution of metal atoms or their compounds on the surface of the protective film. Figure 3 shows the Auger electron spectrum obtained by performing Auger analysis on a protective film made of carbon with a distribution of metal atoms (Co in this example) formed on its internal and external surfaces, which is suitable for the present invention. be. From this figure, it can be seen that the strong spectrum of carbon C was measured w4, and the metal atoms attached to the surface of the protective film did not cover the entire surface of the protective film. In other words, the vertical axis of this figure shows the spectral intensity, and its size represents the relative amount of atoms. Further, the horizontal axis indicates the energy level, and exhibits a spectrum unique to atoms, and in this example, spectra of three elements, carbon C, oxygen O, and cobalt Co, appear. Therefore, carbon is present in the highest amount on the surface of the protective film due to its strength, followed by oxygen and cobalt. If the spectral intensity ratio of each of these elements is determined, it becomes the surface atomic occupancy of each element, and in this example, the surface atomic occupancy of cobalt is about 10%. According to experiments conducted by the present inventors, in order for the lubricant to sufficiently cover the surface of the protective film, it is necessary to use gold g, which is an intervening substance that strengthens adhesion. t
The surface concentration of yX molecules or their compounds (here defined as surface atom occupancy) must be 0.5% or more in terms of atomic ratio, and 80% or more in order not to impair the sliding properties of the protective film. %, preferably from 3 to 60%. For example, the following method can be used to make metal atoms exist on the surface of the protective film. l. After forming the protective film, sputtering is performed using a material made of a specific metal element as a target, or the metal atoms are attached to the surface of the protective film by vacuum evaporation. 2. After the protective film is formed, plasma is generated using a gas containing a specific metal compound as a raw material, and the metal or compound containing the metal is attached to the surface of the protective film. 3. After forming the protective film, it is immersed in a solution containing a specific metal element, dried, and a substance containing the metal is attached to the surface. 4. By performing sputtering using a carbon material containing metal atoms as a target, a carbon film containing the metal atoms is formed. 5. Metal targets and carbon material targets! A carbon film containing the metal atoms is formed by arranging them individually and sputtering them at the same time. 6. Sputtering or plasma CVD of carbon material
A current is applied to the metal wire near the substrate to heat the metal wire, causing metal elements to fly out, forming a carbon film containing the metal atoms. After forming a carbon film containing metal atoms using methods 2, 4, and 5.6 above, the effect will be enhanced if the surface is slightly etched with oxygen plasma to increase the density of metal atoms on the surface. In addition, after forming a film containing metal atoms, by leaving it for a certain period of time under conditions of high water vapor partial pressure, the metal atoms become hydroxides or ions and are evenly distributed on the carbon film surface, making it even more effective. be. Basically, any metal is effective as the metal atom used in the present invention, but transition metal elements classified in the periodic table (a) to (a) or metal elements whose ionization potential is lower than that of hydrogen are preferable. be. These elements include, for example, Sc, Ti, V, Cr, Mn, Fe, Go
, Ni, Y, Zr, Nb. Mo, Cu, Pd, Ag, H
f, Ta, W, I r, P t, Au, AI, Ga, I
n, Ge, Sn, Pb, Ba, Ca, Mg. Lit
Examples include Na, K, Be, etc. . Among these, especially C r p F a * C o * N
Elements in the group consisting of ITAQ, Sn, etc. have a large effect, and can be easily attached by a process such as sputtering, which is the same as forming a protective film, so they are preferred from the standpoint of compatibility with the m-manufacturing process. ．． On the other hand, the lubricant used in the present invention is preferably a compound containing fluorinated carbon in its main chain, and is represented by the general formula *Rl (CnF+++Ok) R2. Here, at least one of R and R2 is a group containing a hetero atom such as O, N, or S, or a benzene/ring, or both, and the main chain CnFm
Ok is, for example, polyfluorinated carbon or barflow polyether with a molecular weight of 500 to 10,000.
n, m are positive integers k is a positive integer or O. The above-mentioned heteroatom- and/or benzene ring-containing group R. ,R
However, the lubricant firmly adheres to the surface of the protective film because it forms a strong bond with the metal element. #! Therefore, the effects of the present invention are not limited to the above-mentioned lubricants, but also apply to saturated fatty acids and their esters. Further, other groups may be added to the above fluorinated carbon. In order to carry out the present invention, the base layer 2 to the protective layer 4 may be formed using a normal film forming apparatus, and the gold Ii4 atoms may be formed separately by sputtering, etc., but the layers up to the protective layer 4 may be formed continuously by sputtering. In the case of shaping the structure, it can be easily realized by simply adding one target for introducing metal atoms. However, when metal atoms are mixed in the protective film itself,
This is more preferable because it can be realized without increasing the number of steps by using a metal-containing protective film raw material target or by plasma CVD of an organometallic compound. [Effect 1] The reason why the lubricant is strongly adsorbed to the protective film and exhibits good lubricating properties according to the present invention is not completely elucidated, but it is thought to be as follows. Many metal atoms easily form coordination bonds with atoms with unpaired electrons such as O, N, S, and P in lubricants, and these bonds are reversible and are considerably stronger than normal intermolecular forces. It is something. In addition, most of the metal atoms that exist on the surface exist in the form of hydroxides or oxides, and hydroxides are particularly easy to form hydrogen bonds with atoms that have the above-mentioned unpaired electrons.
In addition, the surface of the protective film is also oxidized to some extent,
This oxygen atom also easily forms coordination bonds with metal atoms. It is thought that this action causes a strong adsorption force between the surface of the protective film material and the lubricant molecules via the gold Ix atoms. [Example} Examples 1 to 3. An example of a magnetic disk having a film formation structure similar to the cross-sectional structure shown in FIG. 1 is shown below. First, a Ni-P plating film was applied in advance to the AQ disk substrate 4 for 10 minutes. Cr underlayer 2, C
An o-Ni alloy magnetic layer 3 and a sputtered carbon protective layer 4 were formed in this order by sputtering. Sputtering of the carbon layer as a protective film was performed by direct current sputtering using a graphite target at an Ar gas pressure of 5 mTorr. Next, Ni atoms 6 are deposited on this substrate by sputtering.
was attached. This substrate was immersed in a Freon solution containing 0.2% by weight of fluorine-based lubricant 5 and then pulled up at a constant speed to form a lubricant layer. As this fluorine-based lubricant, AM2001 (trade name) manufactured by Montefloss was used. The magnetic disk disc manufactured in this way was subjected to a contact start stop (CSS) tester.
We investigated its durability. The results are shown in Table 1, and the CSS life exceeded 30k cycles, which is one of the practical evaluation criteria, and the increase in the friction coefficient during the test was also small. In addition, as is clear from comparing Examples 1 to 3,
There is a difference in CSS life depending on the proportion of metal attached, and better characteristics are obtained when there is less than too much. However, although not exemplified in this table, if the amount is extremely low, the effect will not be sufficient, and for practical purposes, 0.5 to 80%, more preferably 3
It was ~60%. The surface atomic occupancy of the metal elements in the table was determined by measuring the Auger electron spectrum of the surface of the protective layer after the metal atoms (N i ) were attached as described above. When a magnetic disk device was assembled using eight magnetic disk disks manufactured in the above process and actually operated,
No abnormality occurred even after 2,000 hours of operation, and when the disk surface was observed thereafter, no scratches or stains were found due to sliding. Examples 4-15. As in Example 1, a Nj. - Different types of metal atoms are attached to the AQ substrate with P plating film by sputtering,
In Example 1, magnetic disks with different adhesion amounts were prepared.
A CSS test was conducted by applying lubricant in the same process as above. The amount of metal atoms on the surface of the protective film was measured using Auger electron spectroscopy in the same manner as in Example 1 above. The results are shown in Table 1, in all cases a CSS life of 30k cycles or more was achieved, and the increase in friction coefficient during the test was also small. [Comparative Example 1] When a lubricant was applied on the carbon without sputtering metal in Example 1 and the same test as in Example 1 was conducted, the CSS life was 15k times, and the friction coefficient increased with the number of CSSs. did. Furthermore, when a magnetic disk drive was assembled using eight such magnetic disks and actually operated, the disks stopped moving after 500 hours because the coefficient of friction increased. [Comparative Example 2] In Example 1, Ni was sputtered to a thickness of 10 nm to completely cover the surface of the protective film, and then a lubricant was applied in the same manner and a CSS test was conducted. ,
Both the magnetic head and magnetic disk were scratched. In particular, the scratches on the magnetic disk had reached the magnetic layer. Table 1 below shows Examples 16 to 20. In the carbon sputtering of Example 1, a mixture of Graphdate and a predetermined amount of metal elements was used as a target instead of graphite, and sputtering was performed to form a carbon film mixed with metal elements. A lubricant was applied to this in the same manner as in Example 1, and the CSS life as a magnetic disk was examined. The results are shown in Table 2, and in all cases, a CSS life of 30k cycles or more was achieved, and the increase in friction coefficient during the test was also small. Table 2 However, M1 in the table represents the composition ratio of the metal elements contained in the target. Examples 21-25. A Ni-P plating film is preliminarily applied to a magnetic disk substrate manufactured by AQ. Cr underlayer, Co-N
The i-alloy magnetic layer was formed in this order by sputtering. Then, in a methane gas atmosphere, high-frequency power was applied so that a negative bias voltage was applied to the disk side, generating plasma and forming a hard, non-quality hydrogenated carbon film.
Next, after sputtering the metal atoms in the same manner as in Example 1, a lubricant is applied, and as in Example 1, C
I did the SS test. As shown in Table 3, the results show that the CSS lifespan is 7.
More than 0k cycles were achieved, and no increase in the friction coefficient was observed. Examples 26-30. In Example 21, a mixture of methane gas and the vapor of the organometallic compound shown in Table 4 was used as the raw material, and plasma CVD was performed in the same manner as in Example 21 to reduce the metal atoms to 1 to 1.
A hard carbon film containing 0% carbon was formed. A lubricant was applied to this substrate and a CSS test was conducted in the same manner as in Example 1. As shown in Table 4, no increase in the coefficient of friction was observed over a CSS life of 70k cycles or more. . Table 3 Table 4 Example 31. A thin film of Co-Ni alloy with a thickness of 500 mm was formed on the surface of a polyester film with a thickness of 10 mm using a vacuum evaporation method, and a thin film of Co-Ni alloy with a thickness of 500 mm was formed on the surface of a polyester film with a thickness of 10 mm. , containing 5% Fe and having a thickness of 0.
A hard carbon film of 0.02 μm was formed. This was coated with the same lubricant as used in Example 1, and cut into 8 mm width to create a magnetic tape. Using this, still images of a VTR were played back, and the time until the playback output decreased by 10% (still life) was measured. As a result, as shown in Table 5, the still life was approximately three times longer than that of [Comparative Example 3] which did not contain Fe, and the damage to the tape surface after the test was slight. Table 5 Example 32. A permalloy film is applied on both sides of a polyimide film with a thickness of 0.2 mm. A recording film for perpendicular magnetization was formed by sputtering a Co-Cr alloy to a thickness of 0.1 μm on top of the perpendicular magnetization film. On top of this, a thickness of 0 containing 5% Fe was formed using the plasma CVD method in the same manner as in Example 3l.
．． A non-quality carbon protective film of 02Ilm was formed. Meanwhile, the same lubricant used in Example 1 was added to 0.2% Freon.
A lubricant solution was prepared in advance at a concentration of 1, and the lubricant was passed through the solution to adhere to the surface. Then, a 3.5-inch diameter disc was cut out from this film.
A slider made of sapphire and having a spherical surface with a diameter of R 30 mm was pressed onto this with a load of 20 g, and this disc was
The state of wear was examined by rotating at 0 rpm. the result,
No wear to the magnetic layer occurred even after sliding for 30 min. [Comparative Example 4] In the same process as in Example 32, a permalloy film, a Co-Cr alloy, and an amorphous carbon protective film were sequentially provided on a polyimide film. However, the raw material gas for the non-quality carbon protective film was methane only, resulting in a protective film that does not contain metal atoms. A disk was cut out from this film in the same manner as in Example 32, and a sliding test was performed to examine the state of wear. As a result, abrasion reached the magnetic layer due to sliding for 8 minutes, and the magnetic layer was destroyed.

【Effect of the invention】

As described above, according to the present invention, the lubricant of the magnetic recording medium can be firmly adsorbed to the protective film, which has a great effect on extending the life of the magnetic recording medium and improving its reliability. Furthermore, sufficient lubricity can be obtained even if the thickness of the protective film is made thinner or the flying height of the magnetic head is lowered, so problems with mechanical properties can be reduced, and this has a great effect on increasing recording density.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the structure of the magnetic recording medium of the present invention;
Figure 2 is a cross-sectional view schematically showing an example of the state of existence of metal atoms or their compounds in the present invention, and Figure 3 is an embodiment of the present invention in which metals or their compounds are dispersed on the surface of the protective film. FIG. 4 is an Auger electron spectrum curve diagram at the outermost surface of the protective film. In the spectrum diagram, 1...substrate; 4...protective layer; compound; molecule/aggregate 2...underlayer; 3...magnetic layer 5...lubricating layer ; 6...Metal or its 7...Metal atom or its compound 8...Metal or its compound molecule

Claims (1)

[Claims] 1. A magnetic recording medium comprising a magnetic recording layer made of at least a ferromagnetic material, a protective layer, and a lubricating layer sequentially laminated on a nonmagnetic substrate, wherein metal atoms are formed on the surface of at least the protective layer. A lubricating layer is applied to the protective layer by uniformly dispersing and adhering an adhesion-strengthening intervening material consisting of at least one of the following: A magnetic recording medium with strengthened adhesive strength. 2. The magnetic recording medium according to claim 1, wherein the adhesion-strengthening intervening substance adhered to the surface of the protective layer has a surface atomic occupancy of 0.5 to 80%. 3. The metal atoms constituting the adhesion-strengthening intervening substance are made of a metal element with lower ionization energy than hydrogen, and the compound thereof is at least one selected from the group of hydroxides, salts, and oxides. 3. The magnetic recording medium according to claim 1 or 2. 4. The adhesion-strengthening intervening substance is dispersed within the protective layer,
Claims 1 and 2, wherein the protective layer is mixed with the protective layer, and a portion thereof is exposed on the surface of the protective layer so that the protective layer is substantially scattered on the surface of the protective layer.
Or the magnetic recording medium described in 3. 5. The magnetic recording medium according to claim 1, 2, 3, or 4, wherein the protective layer is made of at least one of carbon, carbide, nitride, and oxide. 6. The lubricant according to claim 1, 2, 3, 4 or 5, comprising a chain organic compound having a terminal group containing an atom having an unpaired electron at at least one end and containing fluorine in the main chain. magnetic recording media. 7. In the manufacturing process of a magnetic recording medium, which includes a step of forming a magnetic recording layer on a non-magnetic substrate, a step of forming a protective layer thereon, and a step of applying a lubricant thereon, the protective layer is Between the step of forming the layer and the step of applying the lubricant, part of the protective layer is partially covered with an adhesion-strengthening intervening substance made of at least one of metal atoms and metal compounds so as not to cover the entire surface of the protective layer. A method of manufacturing a magnetic recording medium, comprising a step of uniformly dispersing and adhering it while exposing it. 8. In the manufacturing process of a magnetic recording medium, which includes the steps of forming a magnetic recording layer on a non-magnetic substrate, forming a protective layer thereon, and further applying a lubricant thereon, the protective layer In the step of forming the layer, the protective layer is composed of a carbon-based material, and at the time of forming the protective layer, an adhesion-strengthening intervening substance consisting of at least one of metal atoms and metal compounds is dispersed and mixed in the protective layer. A method for manufacturing a magnetic recording medium, comprising the step of forming the adhesion-strengthening intervening substance substantially scattered on the surface of the protective layer by exposing the intervening substance on the surface of the protective layer. 9. In the step of forming a protective layer containing the adhesion-strengthening intervening substance, sputtering is performed using a carbon-based target containing the adhesion-strengthening intervening substance, or sputtering is performed using a carbon-based target containing the adhesion-strengthening intervening substance and a carbon-based target. 9. The method of manufacturing a magnetic recording medium according to claim 8, wherein the step of preparing separately and sputtering these simultaneously or alternately. 10. As a step of forming the above-mentioned protective layer, an organic compound vapor containing a metal element, which is one of the above-mentioned adhesion-strengthening intervening substances, or a mixed vapor of a compound containing a metal element and an organic compound is decomposed in plasma in the raw material gas. 9. The method of manufacturing a magnetic recording medium according to claim 8, wherein the step of forming the magnetic recording medium is by a chemical vapor phase method. 11. A claim in which the step of forming the protective layer is a step of generating plasma with a mixed gas of an organic compound as a carbon raw material and an inert gas and performing plasma CVD, and at the same time sputtering the adhesion-strengthening intervening substance. Item 8. A method for manufacturing a magnetic recording medium according to item 8. 12. The metal atoms constituting the adhesion-strengthening intervening substance are:
Consists of metal elements with lower ionization energy than hydrogen,
and the compound is at least one selected from the group of hydroxides, salts and oxides.
9, 10 or 11. The method for manufacturing a magnetic recording medium according to 11. 13. Claims 7, 8, 9, 10, wherein the protective layer is formed with a concentration gradient such that the amount of the adhesion-strengthening intervening substance is more distributed on the surface than inside the layer.
13. The method for manufacturing a magnetic recording medium according to 11 or 12. 14. The protective layer according to claim 7, 8, 9, 10, 11, 12, or 13, wherein the adhesion-strengthening intervening substance is formed to have a surface atomic occupancy of 0.5 to 80%. A method for manufacturing a magnetic recording medium. 15. In the step of applying the lubricant, a chain organic compound having a terminal group containing an atom having an unpaired electron at at least one end and containing fluorine in the main chain is used as the lubricant. 7, 8, 9, 10, 11, 12, 1
15. The method for manufacturing a magnetic recording medium according to 3 or 14. 16. A magnetic disk comprising a non-magnetic disk substrate as the non-magnetic substrate in the magnetic recording medium according to claim 1, 2, 3, 4, 5 or 6. 17. Equipped with a plurality of magnetic disks mounted on the same rotating shaft at predetermined intervals, a magnetic head that reciprocates in the radial direction on these rotating magnetic disks, and a magnetic head drive means for driving the magnetic disk. 17. A magnetic disk device, wherein the magnetic disk is the magnetic disk according to claim 16.